Alkaline oven cleaning composition

ABSTRACT

An alkali metal hydroxide and water solution having incorporated therein nitrogen-containing anionic surfactants combined with a polyhydric alcohol to form the active concentrate of a composition for cleansing food residue and soil from preheated surfaces of cooking ovens, grilles and the like. The particular anionic surfactants present in the concentrate have the important function of inhibiting the corrosive action of the concentrate on the human skin and mucuous tissues and consist specifically of the sodium salts of the condensation product of coconut fatty acids with a complex of polypeptides and amino acids derived from proteins (Maypon SK), of a complex of polypeptides and amino acids derived as a hydrolysate from proteins (Polypeptide No. 37) and of an amido methylated lauric acid (Sodium N-Lauroyl Sarcosinate Sarkosyl NL-97). The concentrate may include a thickening agent to render it surface adhering and additionally may be packaged in an aerosol container for expulsion therefrom by a propellant with or without a foam-forming and foamstabilizing agent.

United States Patent [191 Eisen Dec. 18, 1973 1 ALKALINE OVEN CLEANING COMPOSITION Howard L. Eisen, Fair Lawn, NJ.

[73] Assignee: Glamorene Products Corporation,

Clifton, NJ.

[22] Filed: July 29, 1971 [21] Appl. No.: 167,450

Related US. Application Data [75] Inventor:

[52] U.S. CI 252/118, 252/90, 252/153, 252/158, 252/159, 252/546, 252/DIG. 10

[51] Int. Cl. A211) 3/16,C11d l/32,C11d 7/06 [58] Field of Search 252/90, 118, 153, 252/154, 156, 159, 527, 546; 424/72 [56] References Cited UNITED STATES PATENTS 3,335,092 8/1967 Perry 252/158 3,031,408 4/1962 Perlman 252/154 2,982,738 5/1961 Schmolka 252/153 2,738,304 3/1956 Arnold 424/72 2,655,480 10/1953 Spitzer et a1 252/90 2,041,265 5/1936 Orthner et a1. 252/354 X OTHER PUBLICATIONS Surface Active Agents Vol. I, A. M. Schwartz et al. 1949, pages 34-36.

Surface Active Agents and Detergents Vol II, A. M. Schwartz et al., 1958, pages 37 & 38.

Oven Cleaners," Consumer Reports, July. 1970, pages 423-425.

The Condensed Chemical Dictionary, Sixth Ed., by Arthur & Elizabeth Rose, 1962, page 39.

Primary Examiner--Leon D. Rosdol Assistant Examiner-Dennis L. Albrecht AttorneyLouis F. Kline, Jr. and Arnold Grant [5 7 ABSTRACT An alkali metal hydroxide and water solution having incorporated therein nitrogen-containing anionic surfactants combined with a polyhydric alcohol to form the active concentrate of a composition for cleansing food residue and soil from preheated surfaces of cooking ovens, grilles and the like. The particular anionic surfactants present in the concentrate have the important function of inhibiting the corrosive action of the concentrate on the human skin and mucuous tissues and consist specifically of the sodium salts of the condensation product of coconut fatty acids with a complex of polypeptides and amino acids derived from proteins (Maypon SK), of a complex of polypeptides and amino acids derived as a hydrolysate from proteins (Polypeptide No. 37) and of an amido methylated lauric acid (Sodium N-Lauroyl Sarcosinate Sarkosyl NL-97). The concentrate may include a thickening agent to render it surface adhering and additionally may be packaged in an aerosol container for expulsion therefrom by a propellant with or without a foam-forming and foam-stabilizing agent.

1 Claim, No Drawings 1 ALKALINE OVEN (ILEANING COMPOSITION This application is a continuation application of application Ser. No. 776,261, filed Nov. 15, 1968, now

abandoned,.which in turn was a continuation-in-part of application Ser. No. 517, I14, filed Dec. 28, 1965', now abandoned.

The present invention relates to a new and improved composition for and method of quickly and? expeditiously removing and cleaning from a surface, such as the interior surface'of acooking oven, all adherent residue of burnt-on fat or other deposits of greasyor oily character;

Among the principaliobjects of the'p'resent invention is the provisioniofa cleanser composition'whichmay be contained in and dispensed from a pressure-tight. container having; a conventional aerosol dispensing valve, said'concentrate being characterized by the fact that it is in the form of a concentrate which includes, inter alia, an aqueous solutionof caustic alkali-which is noncorrosive and so produces no harmful effects on theskin should any of the concentrate contact the skin during use of the cleansing composition. Theconcentrate is dispensed from the aerosol package by a propellant contained therein, which propellant is completely inert with respect to and substantially insoluble in the concentrate. Instead the propellant forms with the concentrate, upon shaking of the package, an emulsion from which the propellant is gradually released tothereby effect upon actuation of the aerosol dispensing valve, discharge of the concentrate from the aerosol package to the surface to-be cleaned. Since thepropellant basically remains not dissolved in the. concentrate, where it is of a specific gravity higher than that of the-concentrate, it is. normally disposedf as a liquid inthe bottom of the. aerosol. containerin underlying relation to the concentrate. However, whenthe aerosol package is vigorously shaken to form the above-mentioned concentrate-propellant emulsion andthe aerosol discharge valve is then opened, a proportion of'the propellant in the form of a vapor is releasedfrom the emulsion into the head space of the container'and maintains therein a gaseouspressure sufficient to expel the emulsion from the container, so that the concentrate, upon its discharge from the container and. impingement upon the surface being cleaned is converted intoafoatn by the expanding action of the gas entrained therein.

ln accordance with the principles of thepresent in vention, the-cleanser concentrate contains as its essential constituents l caustic alkali (whichmay be either sodium: hydroxide or potassiumhydroxide-)';.(2) a nitrogen-containingsurfactant of the anionic class, with or without a fatty acidsoap as afoam stabilizing'agent; (3)- a high boiling, essentially non-evaporative polyhydric alcohol; and (4) water in which the foreging constituents aredissolved to form an aqueous solution thereof.

As has been indicated above, the propellant employed in conjunction with such aqueous solution of concentrate packaged in an aerosol" container is of a kind which not only is neither substantially hydrolyzable or degradable in the presence of the concentrate but also is substantially insoluble therein so that it combines with the-concentrate only in the form. ofan emulsion.

'The caustic alkali employed, either sodium hydroxide or potassium hydroxide, is. readily soluble in water, the proportion of alkali used based on the total: weight of the concentrate ranging from 0.5 to 5 percent as against a water content of from 30 to percent by weight of the concentrate. This exceedingly small ratio of caustic alkali to water in the concentrate provides important advantages for the concentrate of the present invention, among which advantages may be listed the fact that water is the least expensive solvent and so materially reduces the cost of the concentrate, and the fact that the relatively high proportion of water present in the concentrate makes it unnecessary to water down the soiled surface being cleaned as a preliminary to application of the cleanser composition and effective activation thereof.

Another most important object of the present invention is to provide a concentrate in the form of an aqueous solution of caustic alkali combined with alcohols and anionic surfactants which not only very markedly inhibits corrosive action of the caustic on the skin but also is not corrosive to ferrous metals of which aerosol containers are made.

Ordinarily aqueous solutions of caustic alkali, particularly when the ratio of caustic alkali to water is high, are quite corrosive to human skin and upon contact cause burns which are of an irreversible reaction or nature. The addition of surface active agents as generally employed in combination with caustic alkali for increasing its saponifying action upon food residue or other fat material in adherent contact with the surface to be cleaned increases the harmful action of the caustic on the skin.

I' have found that the use of certain nitrogencontaining anionic surfactants combined with polyhydric alcohols in an aqueous solution containing not more than 5 percent of caustic alkali and from 30 to 70 percent of water by weight of the concentrate provides a concentrate which is effective for use in quickly and easilycleaning adherent food residue and soil from the surfaces of cooking ovens, barbecue grilles and other surfaces made of alkali resistant materials, which has no corrosive actionon the skin nor on ferrous metals, which is relatively non-volatile under normal conditions of use and may be safely admixed with various chlorofluoro-carbon base and hydrocarbon propellants and mixtures thereof for use in aerosol containers to yield a non-flammable pressure-expelled cleansing composition, which is compatible with a fatty acid soap when introduced into the concentrate for the production of a stabilized foam, and which may be safely applied to a soiled surface that has been preheated to a temperature of about 200 F. to effectively increase the rate of saponifying reaction of the concentrate upon the carbonized and non-carbonized fats and soil residue desired to be removed from the surface to be cleaned. Further, I have found that in use of the concentrate of the present invention it is not necessary to employ vinegar or any other agent to neutralize the caustic alkali, nor is it necessary thatthe user of the concentrate wear gloves or other protective articles, since the caustic in the concentrate is so inhibited as to have no corrosive effect upon the human skin and mucuous membranes. By concentrate as used herein is meant the aqueous solution of caustic alkali, polyhydric alcohols and anionic surfactants hereinafter specifi'cally described with or without additives and excluding therefrom the propellant.

The anionic surfactants employed in the concentrate of the present invention may be any one or a mixture of the following:

3 ,779 ,9 3 3 3 4 l.Maypon SK (manufactured by the Maywood Diabove specified, as well as the surfactant marketed as vision of Stepan Chemical Company), consisting of the Sarkosyl NL-97, which is the sodium salt of an amidosodium salt of the coconut fatty acid amide of protein methylated lauric acid, have the common property hydrolysate (complex polypeptides obtained from prowhen combined with the caustic alkali and alcohols of tein hydrolysis), having the structure: 5 effectively inhibiting the corrosive action of the caustic upon the human skin and mucosa.

T 3' Also included in the concentrate is a humectant in R,CN(CCNC) -C-0-M the form of relatively non-evaporative, high boiling I polyhydric alcohols, such as glycerol, ethylene glycol,

H H l0 propylene glycol and dipropylene glycol. These glycols not only prevent too rapid drying out of the concenwherein trate but also act as humectants for maintaining the n is an integer averaging 4 which is controlled by the caustic alkali in an active state when the aqueous condegree of hydrolysis, centrate is applied to a surface to be cleaned which has R represents hydrogen or hydrocarbon groups having been preheated to a temperature of 200 F.

from 1 to 7 carbon atoms, While the concentrate of the present invention con- R, represents coconut fatty acid, and sisting essentially of an aqueous solution of the caustic M represents sodium,potassium,ammonium,triethaalkali, the surfactants and the glycols as above mennolamine and other organic amines. tioned may be effectively used when applied as a liquid This compound, MAYPON SK, contains from 36 to to the soiled surface to be cleaned, its use is greatly fa- 43 percent of the characterizing sodium salt as its accilitated when it is applied in the form of a foam distive ingredient and from 14.4 to 16.9 percent proteins, pensed from an aerosol container. To this latter end the as computed from Kjelda h, Nitrogen determinations concentrate preferably may include a foam-forming showing 2.3 to 2.7 percent Nitrogen. and stabilizing agent in the form of an anionic fatty acid 2. Polypeptide No. 37" (manufactured by Maysoap, which is obtained through introduction into the wood Division of the Stepan Chemical Company, conconcentrate of oleic acid and an alkanolamine, such as sisting of the sodium salt of a complex of polypeptides monoethanolamine, diethanolomine or triand amino acids derived as a hydrolysate from protein ethanolamine. This fatty acid soap constituent of the degradation, having the structure: 3 concentrate serves not only as an additional emulsify- TOHHO l? iiill'ii l l l R R R R R R wherein ing agent for the propellant when the concentrate is packaged in an aerosol container but also as a stabilizing agent for the foamed concentrate expelled from the 40 pressurized container when the discharge valve thereof is opened. The alkanolamine further combines and acts synergistically with the caustic alkali to more effectively activate the cleansing property of the composition.

Combined with the caustic alkali concentrate in the aerosol container is a propellant which may be any one n is an integer averaging 20 which is controlled by the degree of hydrolysis,

R represents hydrogen or hydrocarbon groups having from 1 to 7 carbon atoms, and

M represents sodium, potassium, ammonium, triethanolamine and other organic amines.

This compound, Polypeptide No. 37, contains from 41 to 45 percent of the characterizing sodium salt as its active ingredient and from 37 to 43 percent protein, as computed f Kjeldahl Nitrogen determinations or a mixture of the following: dlCl'llOlO difluoro methshowing 5.92 to 6.88 percent nitrogen. fine C ienetron l2 manufactured by General Chemi- Sodium N Lauroyl Sarcosinate (e'gq cal Division; Freon l2 manufactured by Freon Divi- SYL NL97", manufactured by Geigy Industrial Sion of d6 w? 9 Chemicals Division of Gelgy Chemical Corporation), manufactured by Kaiser Chemical DlVlSlOl'l of Kaiser consisting of the sodium salt of an amido-methylated Aluminum 84 Chemical 531653 Inc-i 150mm lauric acid having the Structure; manufactured by Pennsalt Chemicals Corporation and Ucon l2 manufactured by Union Carbide Chemicals Corp.) and dichloro tetra-fluoro ethane (Genetron O H O 114 General Chemical; Freon 114" l.l. duPont II I II de Nemours; K 114 Kaiser Aluminum; lsotron R'TCTT CO M 1 l4 Pennsalt Chemicals and Ucon 1 l4" Union OH H Carbide).

' In lieu of the above described propellant, there may be employed in the composition of the present invenwherein tion other con-ventional hydrocarbon propellants, such R represents the fatty substituent from lauric acid as butane, isobutane, propane and mixtures thereof. By containing from 10 to ll carbon atoms, and substituting a judicious quantity of such hydrocarbon M represents sodium, potassium,ammonium,triethapropellant for the fluorocarbon propellant content of nolamine and other organic amines. the composition to be sprayed from an aerosol conlt has been found that the protein type surfactants tainer, as by introducing into the composition a hydrocarbon propellant in an amount of from 3 to 4.5 percent by weight of the composition as against about 6 percent by weight of the aforesaid fluoro carbon propellant, the composition containing the hydrocarbon propellant is non-flammable.

The non-flammable property of the composition containing the hydrocarbon propellant in accordance with the present invention is an important attribute thereof since it is desirable, for most effective cleansing of oven soils, to spray the composition into the oven pre-heated to a temperature of approximately 200 F. This elevated temperature of the surfaces to be cleaned not only potentiates the action of the caustic on the oven soils, but also effects such instant volatilization of the propellant vapors as to enable them to rapidly flash off and be carried away by the hot air convection currents.

All of the above-mentioned propellants are substantially insoluble in the aqueous concentrate, but instead combine there-with to form a liquid emulsion which, upon its discharge from the dispensing container, and impingement against the surface to be cleaned, effectively forms a stabilized blanket of foam over said surface to soften, dissolve and emulsify the burnt on fats and other deposits so that the same may be readily removed by a simple wiping treatment.

When, however, it is desired to use the concentrate of the present invention as a liquid preparation as distinguished from a foam-forming composition, it may be desirable to incorporate in the concentrate, in lieu of the fatty acid soap stabilizer, a thickening agent such as sodium carboxy methyl cellulose (CMC), amylo pectine starch or other compatible additive which is soluble or at least readily dispersable in the concentrate to render it more or less viscous as may be desired so that it may properly blanket and adhere to the surface to be cleaned.

It will be noted from the formulae examples hereinafter set forth that in both the liquid and the foamforming compositions, the percentages by weight of the basic ingredients thereof which act synergistically to maximally inhibit the corrosive action of the caustic alkali upon human skin and mucuous membranes, namely, the caustic alkali combined in aqueous solution with the aforementioned polyhydric alcohols and anionic surfactants, may be varied within the following ranges:

Caustic Alkali 0.5% to 5.0%

Polyhydric Alcohol 20.0% to 40.0%

Maypon SK" 0.3% to 5.0%

Poly peptide No. 37 1.0% to 20.0%

Sodium N-Lauroyl Sarcosinate 0.5% to 5.0%

Water 30.0% to 70.0%

Similarly, the additives incorporated in the concentrate, to wit, the thickening agent in the case of the liquid preparation and the foam stabilizer with or without additional thickening agents in the case of the foamforming preparation, may vary as desired in any amount up to 5 percent in each instance.

As for the propellant, its percentage (also by weight I of the total foam-forming composition packaged in the dispensing container) may vary in amount as may be necessary to provide in the aerosol container the requisite vapor pressure for effecting complete discharge therefrom of the cleanser contained therein and effective foaming thereof. which pressure should be within safe limits for the container in which the cleanser is packaged.

The following examples are illustrative of the present invention and provide compositions which have exceptionally high cleaning power when used to remove food residue and burnt-on fat and grease deposits from the 5 surfaces of ovens and the like. Further, and of equal importance, is the fact that in all of these illustrative compositions, the corrosive effect of the caustic alkali content thereof is inhibited to minimize burns or other irreversible injury to the user upon contact of the composi- 10 tion with the skin.

In all of the following examples, the percentage values are by weight of the entire composition:

EXAMPLES OF LIQUID (NON-AEROSOL) l 5 PREPARATIONS Ex.1 Ex.2 Ex.3 Ex.4 Ex.5 %by%by %by %by%by Wt. Wt. Wt. Wt. Wt. Sodium Hydroxide 2.80 2.80 2.80 5.00 Potassium Hydroxide 3.00 Propylene Glycol 20.00 26.90 20.00 25.90

Dipropylene Glycol 40.00 Maypon SK" 2.00 2.00 4.00 2.00 5.00 Polypeptide No. 37 1.00 1.00 2.00 1.00 15.00 Sodium N-Lauroyl Sarcosinate (anhydrous) 0.75 0.75 1.50 0.75 5.00 Carboxy Methyl Cellulose 0.50 1.00 Amylo Pectine Starch 4.00

Water 69.45 69.20 30.00

Total 100% 100 100% 100% 00% EXAMPLES OF FOAM-FORMING (AEROSOL) COMPOSITIONS Ex.6 Ex.7 Ex.8 Ex.9 by by by by Wt. Wt. Wt. Wt.

Sodium Hydroxide 2.80 2.80 2.80 Potassium Hydroxide 3.00

Propylene Glycol 20.00 20.00 20.00

Dipropylene Glycol 20.00 Maypon SK" 2.00 2.00 4.00 2.00 Polypeptide N0. 37" 1.00 1.00 2.00 1.00 Sodium N-Lauroyl Sarcosinate (anhydrous) 0.75 0.75 1.50 0.75 Oleic Acid 030 0.30 0.30 Triethanolamine 0.60 0.60 0.60

40 Water 66.55 66.35 63.70 66.55

Propellant 6.00 6.00 6.00 6.00

Total 100 100% 100% 100% FURTHER EXAMPLES OF FOAM-FORMING (AEROSOL) COMPOSITIONS Ex.10 Ex.l1 Ex.12 Ex.13 by by by by wl. wt. wt. wt. Sodium Hydroxide 3.0 4.0 Potassium Hydroxide 4.0 4.0

Propylene Glycol 50.5 50.0 42.0

Dipropylene Glycol 46.0 "Mapon SK (45% solids) 10.0 3.5 6.0 Polypeptide No. 37 (50% solids) 8.0 3.5 6.0

Sodium N-Lauroyl Sarcosinate (anhydrous) Oleic acid 0.4 0.3

Triethanolamine Monoethanolamine 5.0 2.0 2.6 3.3 Veegum" 0.5 1.0 1.0 0.2 Hydroxyethyl cellulose Sodium carboxymethyl cellulose Kelzan 0.2 Water 30.0 35.0 40.0 38.0

Totals 100% 100% 100% Assessed Total Water Content 36% 40% 44.3% 45.0%

Ex.14 Ex.15 Ex.16 Ex.17 by by by by Wt. Wt. wt. wt. Sodium Hydroxide 2.8 2.5 Potassium Hydroxide 3.0 4.0 Propylene Glycol 46.2 44.0

gg 'lf rd 3 60 3 2 In use of the product of the present invention, the apon sol s polypeptide 37 (50% preferred procedure 15 to apply it directly upon the sur- SOIidS) face to be cleaned, preferably after it has been pre- Sodium N-Lauroyl sarcosinaw (anhydrous) 2'0 3) heated as aforesald, as by spraying the same, when pre Olcic acid 0.2 0.2 5 pared as a foam-forming composltlon pursuant to Ex- T'lflham'amim amples 6 to 17 as above set forth, from a pressurized Monoethanolaminc 2.0

s n {13 dispensing container to form a covering blanket of Hydroxyethyl cellulose foam, or by brushing or otherwise applylng the same, ig m 0 1 when prepared as a non-aerosol composition pursuant to the foregoing Examples 1 to 5, so as to completely "Kelzan" 0.5 Water 420 40.0 3 .3 cover the soiled surface. After the solllng deposits on Totals 100% 00% 00% 100% the surface undergoing treatment have been softened Assessed Total and emulsified by the applied cleanser composition,

459% 459% 455% 393% they may be readily removed by a simple wiping operation with a damp cloth or sponge. In the case of heavier than normal deposits, a second application of the cleanser may be required followed by the wiping treatment. No preliminary wetting of the soiled surface is necessary, and neither is it necessary to use vinegar or any other agent for neutralizing the active caustic ingredient of the clean-ser composition.

Except for the surfactants Mapon SK and Polypepl5 tide 37 and the water in the above Examples 10 to 17 all of the remaining ingredients of the compositions are included therein on essentially an anhydrous basis. Also, in hese Examples 10 to 17, the percentage stated for the several constituents of each composition are ex- 20 elusive of the propellant which as previously Stated is While I have described herein several embodiments resent i tPorce s: g z z r R2 Sufficient to of my mventlon, it will be apparent that it is susceptible p o e aeroso con amer as of various other changes and modifications without dea Spray whlch i to foam lmpmgemem parting from the general principles or real spirit "P the Surface cleanedthereof, and it is to be understood accordingly that it In those composmons of Examples 10 to 17 wherem is intended to claim the present invention broadly, as

the water content thereof is limited to substantially less we as Specifically, as indicated by the claims than 50 percent of the total weight of the composition, pended hereto the humectant content is increased proportionately as I l i set forth and also there is included in the composition, 1, A li id iti f cleaning oven, grill and with or Without the Presence therein 0f the Olelc acid similar surfaces which inhibits the corrosive action soap as a foam Stabilizing age a pr p i thereof on human skin and mucous tissues consisting amount of water thickening agents to further stabilize essentially of an aqueous solution of about -5 to 5 the foam. These thickening agents, in addition to those parts by weight of sodium hydroxide, about 20 parts by previously mentioned and which serve to stabilize the weight of propylene glycol; about 2 parts by weight of foam and to increase its ability to adhere to vertical sura compound having the following general formula: faces, may be of the organic type or the inorganic type as follows: 7 W

ORGANIC T f i T i Hydroxy ethyl cellulose H H H Methyl cellulose polysaccharides (Kelzalf' manufactured by where R represents hydrogen and hydrocarbon groups Kelco p y) 5 having from l to 7 carbon atoms, R represents fatty substituent of lauric acid made from coconut oils, M

INORGANIC (clays and beneficlated clays) represents sodium, and m is an integer averaging 4 and Refi alciu bfintonite y manucontrolled by the degree of hydrolysis; about 1 part by factured by HM. Johnso weight of a compound having the formula:

l? i l iii l' i i i i iii l lil l Il(|ICN([Z--C(N |-CN--(|IC- ,,NCC-NC|-CO-M H R R R R R R Complex, colloidal, magnesium aluminum silicate wherein R represents hydrogen and various hydrocar- (Veegum manufactured by RT. Vanderbilt bon groups having from 1 to 7 carbon atoms, n is an in- Co., Inc.) teger averaging 20 controlled by the degree of hydroly- It is well known that reaction rates approximately sis and M is sodium; about 0.75 parts by weight of a double for each 10 C. (18 F.) rise in temperature, so Compound represented by the formula:

that when the cleansing preparation of the present invention is applied to a surface pre-heated to about 200 s 0 F., representing an increase of some 125 F. over normal room temperature, the preparation will act on and clean soiled surfaces more than 100 times faster than H it would at room temperature. Thu it has been found wherein R represents the fatty substituent of lauric acid that the composition of the present invention effecmade from coconut oil, M represents sodium;about 0.3 tlvely cleans ovens of burnt-0n fatty food residue and parts by weight of oleic acid; about 0.6 parts by weight the like within a matter of only several minutes, ordiof tri-ethanolamine; and, from about 30 to about narily if properly applied in about three minutes. parts by weight of water. 

